DISSERTATION RESEARCH: The effect of nitrogen deposition on plant community dynamics across local and regional scales

加州的快速城市化使残留的橡树稀树草原生态系统暴露于不断增加的大气氮（N）沉降水平。 沉积的氮进入生态系统，使植物暴露于它们可能不适应的数量和化学形式的氮。氮沉降在整个景观中的分布并不均匀，而是在多个尺度上变化。这导致土壤中氮的不均匀分布，这可能会改变植物群落下增加氮输入。本研究的目的是调查氮沉降如何与环境条件相互作用，这些条件在区域（例如，降雨）和当地（例如，光）规模，结构植物群落。结合观察和实验的方法将被用来了解的模式和过程，橡树稀树草原接收氮沉降和植物响应它。这项研究将研究通过氮沉降影响植物群落在橡树稀树草原的具体过程。了解嵌入在不断变化的景观中的自然区域的动态对于管理和保护工作至关重要。管理人员担心氮沉降对入侵物种的影响，以及这如何影响牧场的牧草质量。在更广泛的区域范围内，研究结果可以为影响氮排放和空气质量的土地利用和监管决策提供信息。

Rapid urbanization of California's landscape exposes remnant oak savanna ecosystems to increasing levels of atmospheric nitrogen (N) deposition. Deposited nitrogen enters the ecosystem and exposes plants to amounts and chemical forms of N that they may not be adapted to. Nitrogen deposition is not distributed evenly across the landscape, but varies across multiple scales. This results in the heterogeneous distribution of N in soil, which may alter plant communities under increasing N inputs. The aim of this research is to investigate how N deposition interacts with environmental conditions, which vary at the regional (e.g., rainfall) and local (e.g., light) scale, to structure plant communities. A combination of observational and experimental methods will be used to understand patterns and processes by which oak savannas receive N deposition and plants respond to it.This research will study specific processes through which N deposition affects plant communities in oak savannas. Understanding dynamics of natural areas embedded within a changing landscape is critical for management and conservation efforts. Managers are concerned about the effect of N deposition on invasive species and how that affects forage quality in grazing lands. At the broader, regional scale, results can inform land-use and regulation decisions affecting N emissions and air quality.